Haha but serious: those fountain pens that cost thousands of dollars are collectible art pieces that aren’t actually optimized for a good writing experience. They’re CEO bait.
Serious hand-writers use fountain pens that mostly cost between $30 and $200. You can get decent ones for $10 but they tend not to be very airtight and quickly dry out.
My #1 practical recommendation is the TWSBI Eco, which is generally around $40 in the west.
